Excessive alcohol use and alcohol use disorders (AUDs) are a leading public health concern in the United States. Excessive alcohol consumption is related to nearly $225 billion in economic costs and over 80,000 fatalities annually. Sexual minority youth (SMY; lesbian/gay, bisexual, transgender, and queer/questioning [LGBTQ+]) are at heightened risk for mental health symptoms and alcohol use due to their unique experiences as sexual and gender minorities (e.g., discrimination, victimization). Their propensity for excessive alcohol use puts them at greater risk for adverse consequences, including the development of an AUD and alcohol related morbidity and mortality. Both the National Institute of Health and the Institute of Medicine have expressed the need for researchers to address health disparities among sexual minorities. Despite identifying the elevated risk for excessive alcohol use among SMY and young adults, researchers have yet to build a comprehensive picture of how modifiable interpersonal (relationships with peers and parents) and contextual (school climate) factors influence their alcohol use. Consequently, there are large gaps in the available research regarding how indicators of risk and protective factors differ between heterosexual and SMY and among subpopulations of SMY (differentiated by gender, sexual minority status, and race/ethnicity). As such, there are no empirically validated prevention or intervention programs addressing SMY and young adult alcohol use. This National Research Service Award (F32) will provide the applicant with the training and resources necessary to address SMY health disparities, setting the stage for continued work in this area as an emerging scholar. To accomplish career and research goals, the applicant requires training in (1) investigating health disparities among sexual minority populations, (2) etiology and epidemiology of alcohol use within a developmental context, and (3) complex quantitative methodologies testing developmental processes and contextual influences. The training program combines mentored research projects with coursework, workshops, and conferences to enable the applicant to build a strong and influential program of research addressing the modifiable interpersonal and contextual factors that contribute to SMY alcohol use. Three research aims are addressed in the current application: (1) Identify modifiable interpersonal and contextual risk and protective factors that contribute to SMY and young adult alcohol use; (2) test the influence of modifiable interpersonal and contextual risk and protective factors unique to SMY (e.g., SMY-specific family support, victimization, school climate) that contribute to SMY and young adult alcohol use; and (3) construct a developmental theoretical model of sexual minority alcohol use that will act as the foundation for writing a K01 award that tests these theoretical associations and propositions at later stages of the applicants career.